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United States Department of Agriculture

Agricultural Research Service

Title: A Highly Regioselective Synthesis of Delta-Lactones from Meadowfoam Fatty Acids

Authors
item ISBELL, TERRY
item Plattner, Beth - INDIANA UNIVERSITY

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 21, 1996
Publication Date: N/A

Interpretive Summary: Industrial lubricants, detergents and cosmetics need new sources of biodegradable materials that have better properties than existing products. Vegetable oils can often meet the needs of industrial applications by providing a renewable resource and a biodegradable product. However, in some industrial applications, physical requirements are too demanding for vegetable oils from current crops such as soybeans, canola, sunflower etc. Fortunately, oils that have potential to meet the industrial demands can be obtained from new crops such as meadowfoam. Meadowfoam oil is made up of a unique set of components that allowed us to make a new material, delta-lactone. We found that delta-lactones could be made in high yield (approximately 90%) under certain reaction conditions. These lactones will be useful in biodegradable lubricants, detergents and cosmetics. In addition, the delta-lactones will provide a new starting material for making other compounds with new properties, that were not previously available to industry. Ultimately, delta- lactones will boost the acreage of meadowfoam by providing a commercial end market for the oil.

Technical Abstract: Meadowfoam fatty acids, when treated with mineral acid catalysts in the presence of polar non-participating solvents, undergo a facile ring closure to form delta-lactones. Perchloric and sulfuric acid catalyze the cyclization at concentrations of 0.6-13 mole equivalents, both neat and in the presence of solvent. Under constant acid concentrations, methylene chloride was found to increase the rate of reaction, the regioselectivity for the formation of delta-lactone, and the overall yield. In the absence of solvent, increased acid concentration improved the yield of lactone but reduced regioselectivity for the delta-isomer. Solvent polarity plays a significant role in the regioselectivity of the cyclization for delta-lactone, with solvents of higher dielectric strength providing larger delta/gamma ratios (38:1) and higher yields up to 92%.

Last Modified: 9/10/2014
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